Replace Thetford 300 manual pump

Portchieboy99

The pressure on the toilet manual pump has dropped, and I gather that the rubber washer has probably given up the ghost.

Easy to but a new one on ebay around £25, but has anyone fitted one themselves? I have talken the handle off the toilet, removed the 2 screws and levered off the top(sealed on). However, taking out a further 4 screws, the gap left seems too small just to pull out the unit.

I didn't want to tug too hard, without asking first.

Thanks.